Process for producing methacrolein and methacrylic acid

ABSTRACT

Methacrolein and methacrylic acid are produced by the catalytic oxidation of isobutylene in the vapor phase with molecular oxygen over a catalytic amount of a mixture of solid metal oxides, represented by the empirical formula SbaVbMocTedWeMfOg, wherein M represents at least one element selected from the group consisting of bismuth, thallium and uranium, and wherein the elemental atomic ratios of said empirical formula have values of a 10, b 0.1-10, c 0.4-15, d 0.1-10, e 0-2, f 0-2 and g 16-127, so as to satisfy the empirical formula.

United States Patent [1 1 Ono et al.

[451 Apr. 22, 1975 7 [75] Inventors: lsao Ono; Teruhisa Sakamoto;

Toshio Hironaka, all of Yamaguchi, Japan [73] Assignee: Toyo SodaManufacturing Co., Ltd., Yamaguchi, Japan [22] Filed: May 30, 1973 [21]Appl. No.: 365,100

[30] Foreign Application Priority Data May 30. I972 Japan 47-53662 Aug.2, I972 Japan 47-77469 [52] U.S. Cl 260/533 N; 252/456; 252/464:

252/469; 252/467; 260/604 R [51] Int. Cl C07c 51/32; C07c 57/04 [58]Field of Search 260/533 N, 604 R [56] References Cited UNITED STATESPATENTS 3,574,729 4/l97l Ganon 260/530 N 3.736.355 5/1973 Croci et al.260/533 N FOREIGN PATENTS OR APPLICATIONS 97l.666 9/1964 United Kingdom260/533 N 2,050,155 5/l972 Germany 260/530 N Primary Examiner-LorraineA. Weinberger Assistant Examiner-Richard D. Kelly Attorney, Agent. orFirm-Oblon, Fisher, Spivak, McClelland & Maier [57] ABSTRACTMethacrolein and methacrylic acid are produced by the catalyticoxidation of isobutylene in the vapor phase with molecular oxygen over acatalytic amount of a mixture of solid metal oxides, represented by theempirical formula Sb,,V,,Mo Te,,W ,M,O wherein M represents at least oneelement selected from the group consisting of bismuth, thallium anduranium, and wherein the elemental atomic ratios of said empiricalformula have values of a=l0, b=0. ll0, c=0.4-l 5, d=0.l-l0, e=02, #0-2and g=l6-l27, so as to satisfy the empirical formula.

12 Claims, No Drawings PROCESS FOR PRODUCING METIIACROLEIN ANDMETHACRYLIC ACID BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention relates to a process for producing methacroleinand methacrylic acid in high yields by the vapor phase catalyticoxidation of isobutylene. More particularly, it relates to a process forthe vapor phase catalytic oxidation which comprises the use of a novelmulti-component catalytic system consisting of antimony, vanadium,molybdenum and tellurium and- /or tungsten and one or more elementsselected from the group consisting of bismuth, thallium and uranium.

2. Description of the Prior Art Substantial research has been done onmethods for producing methacrolein and methacrylic acid by the catalyticvapor phase oxidation of isobutylene. Numerous catalyst systems havealso been studied and reported for this oxidation reaction. Of primaryimportance, from the industrial point of view, is the achievement of thehighest possible single-pass yield of useful products, because it isgenerally uneconomical to recover and recycle unreacted isobutylene.However, as the conversion rate of isobutylene is increased, thequantity of undesirable products produced, such as carbon dioxide,carbon monoxide and acetic acid also increases because of gradualoxidative decomposition. This causes a decrease in the selectivity formethacrolein and methacrylic acid. In addition to the requirement forhigh single-pass yields of product the catalyst system must also have asufficient activity as well as possess a sufficient lifetime so as to beuseable in industrial applications.

Although various catalyst systems have been reported in connection withthe production of methacrolein and methacrylic acid from isobutylene,satisfactory results have not been attained with these systems. Forinstance, Japanese Patent Publ. No. 9872/1964 discloses an oxidecatalyst system consisting of molybdenum, vanadium and phosphorus andJapanese Patent Publn. No. 3164/1968 discloses an oxide catalyst systemconsisting of molybdenum, vanadium and bismuth. In both of thesecatalyst systems extremely high reaction temperatures, ranging from 450to 550C are required, which shortens the lifetime of the catalysts. Alsothe single-pass yields of methacrolein and methacrylic acid areinsufficiently low. Thus, both of these catalyst systems are consideredto be industrially unsatisfactory.

Example 3 of Japanese Patent Publn. No. 19485/1970 discloses the use ofacatalyst system consisting of molybdenum, antimony, tellurium, andsodium or potassium which produces a fairly good singlepass yield ofmethacrolein and methacrylic acid. However, the activity of the catalystis insufficient, and also the lifetime of the catalyst is limited whensodium or potassium are lacking. In another catalyst system consistingof iron, antimony, tellurium and vanadium (or molybdenum or tungsten) asdisclosed in Japanse Patent Publn. No. 1607/1972, a high combustion rateof isobutylene is achieved resulting in single-pass yields ofmethacrolein which amount to only about 60 percent, with the by-productof methacrylic acid limited to only about 1 to 2 percent.

A need, therefore, exists for a catalyst system which promotes theoxidative conversion of isobutylene to methacrolein and methacrylic acidin high single-pass yields while achieving high selectivity formethacrolein and methacrylic acid.

SUMMARY OF THE INVENTION Accordingly, one object of the presentinvention is to 7 provide a catalyst system which promotes the oxidativeconversion of isobutylene to methacrolein and methacrylic acid in highyields and high selectivity.

Another object of the present invention is to provide a multicomponentcatalyst system for the oxidative conversion of isobutylene whichcontains antimony in addition to at least three other polyvalent metalelements.

Briefly, these objects and other objects of the invention as hereinafterwill become readily apparent can be achieved by use of a solid metaloxide catalyst for the vapor phase, catalytic oxidation of isobutylenewith molecular oxygen which comprises a mixture of metal oxides havingthe empirical formula Sb V Mo Te W,.M,0,,, wherein M represents one ormore elements selected from the group consisting of bismuth, thalliumand uranium and wherein the elemental atomic ratios of said empiricalformula have values of a=l0, b=0.1-l0, c=0.4-l5, d=O.l-l0, e=02, f= 02and g=l6l27, so as to satisfy the empirical formula.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention forthe catalytic conversion of isobutylene to methacrolein and methacrylicacid in high yields a solid metal oxide catalyst system is used which isrepresented by the empirical formula Sb,,V,, Mo Te W Mp wherein M is oneor more elements selected from the group consisting of bismuth, thalliumand uranium and a, b, c, d, e,fand g are the atomic ratios of theelements. The atomic ratios encompass the ranges ofa=l0, b=0.l-lO,c=O.4-l5, d=0. l-lO, e=0-2, FO-Z and g=l6-l27. Optimum catalystperformance is obtained when the atomic ratios in the catalystcompositions preferably encompass the ranges of 0 10, b=1-4, c=l-8,a=28, e=().ll and f=().1l and g satisfies the empirical formula.

The catalyst of the present invention may be employed as is, or it maybe mixed with a suitable carrier such as diatomaceous earth, silica,alumina, titanium oxide, carborundum pellets, zirconium oxide to improvethe physical strength, thermal stability, reactivity, selectivity andthe like of the catalyst. Although the catalyst of this invention may beprepared by any of several conventional methods, it is preferablyprepared by uniformly mixing aqueous solutions of each componentfollowed by isolating and drying the mixture.

In one embodiment of the preparation, for example, a catalyst isprepared which uses antimony trioxide as the source of antimony,ammonium meta-vanadate as the vanadium source, tellurium dioxide as thetellurium source, ammonium molybdate as the molybdenum source, ammoniumtungstate as the tungsten source, bismuth nitrate as the bismuth source,thallium trichloride or thallium nitrate as the thallium source anduranyl nitrate as the uranium source. First, ammonium molybdate isdissolved in warm water into which an aqueous solution of ammoniummetavanadate is dissolved and mixed. Aqueous solutions of ammoniumtungstate and/or tellurium dioxide are added to the mixture andthoroughly stirred. Aqueous solutions of reaction may be carried out attemperatures ranging a wide range, but it is preferable to use a feedgas combismuth nitrate and/or thallium trichloride and/or urapercentisobutylene, about 60 mole percent air and nyl nitrate are added, andantimony trioxide is mixed about 35 mole percent steam was fed into thereactor in the composition. The composition is thoroughly while it washeated. The apparent contact time was sestirred, and then isconcentrated by evaporation. If delected to fall within the range of 4to 7 seconds at a consired, a suitable carrier material as indicatedabove may stant reaction temperature in the range of 360 to be added.The slurry is further concentrated and dried, 430C. The gas evolved fromthe reactor was cooled by and then calcined in air at a temperature inthe range an ice water solution and by a dryice methanol soluof 400 to600C. The calcination temperature is not tion. After passage of the gasthrough the cold traps, critical, but it is desirable to conduct thecalcination at the evolved gas and the liquids trapped in the dry-ice atemperature of 460 to 540C for several hours. 10 bath were analyzed bygas chromatography and par- Suitable reactors for the oxidation ofisobutylene intially by titrimetry and the constituents and theirreclude either fixed bed or fluid bed reactors which conspectivequantities were determined.

tain the catalyst of this invention. The gas fed to the re- EXAMPLE 1actors is composed of isobutylene and molecular oxygen to whichnitrogen, carbon dioxide, steam or the like may optionally be added asan inert diluent. The

Is An 18.0 gram amount of ammonium paramolybdate (NH Mo O .4l-l O wasdissolved in 400cc of distilled water, and 11.6 grams of ammoniummetavanadate NH VO was added and dissolved in the molybdate solutionwith stirring while being heated over a hot water bath. An 8.0 gramamount of tellurium dioxide TeO and 73.2 grams of antimony trioxide Sb Owere added to the solution and it was thoroughly stirred. The resultingsolution was concentrated by evaporation and the residue was dried. Thedried residue was punched into 25 tabloids of 3mm diameter which werecalcined at a temperature of 520C for 5 hours. A catalyst having acomposition of Sb:V:Mo:Te=10:2:2:1 (atomic ratio) was obtained in thismanner.

The oxidative conversion of isobutylene was conducted over this catalystat a reaction temperature of 400C and a contact time of 5.0 seconds. Theresults are shown in Table I wherein the conversion of isobutylene is96.4 percent, the selectivities of methacrolein and methacrylic acid74.0 and 7.6 percent respectively; and the composite single-pass yieldof methacrolein from 250 to 500C, preferably ranging from 350 to 420C.Though the apparent contact time of the reactants greatly variesaccording to the reaction tempera- 20 ture and the composition of thefeed gas, a range of 0.5 to 20 seconds, preferably a range of l to 12seconds is suitable. The composition of the feed gas may vary overposition which is in the range of l to 10 mole percent isobutylene, 20to 90 mole percent air and l to 50 mole percent steam.

The isobutylene which is used as the raw material of the invention neednot be ofa high purity. Even if other saturated or unsaturatedhydrocarbons such as ethylene, propylene, propane, butane, and the likeare present, these substances are not oxidized but merely pass throughthe reactor, as would any inert diluent. Similarly it is not alwaysnecessary to use pure oxygen as the source of oxygen. Air is a suitablesource of oxygen and and methacrylic acid is 78.6 percent. 15 desirablefor economical reasons.

By using the catalyst of this invention in conventional EXAMPLE 2processes, such as is disclosed in Japanese Patent A catalyst with acomposition of Sb:V:Mo:- Publn. No. 7881/1967, it is possible to producemeth- Te=l0g2:4:2 t i ratio) was prepared in a manner acrolein andmethacrylic aCid from isob yl n and similar to that described inExample 1. The oxidative simultaneously butadiene from n-butenes by theoxidaconversion was conducted under the same reaction tion of a Chydrocarbon fraction. conditions as described in Example 1. The resultsob- Having generally described this invention, a further tained areshown in Table I, wherein the conversion of understanding can beobtained by reference to certain isobutylene is 97.5 percent, theselectivity of methacro- 5 specific examples which are provlded hereinfor purlem is 76.0 percent, the selectivity of methacrylic acid pose ofillustration only and are not intended to be limis 5.3 percent, and thecomposite single-pass yield of iting unless otherwise specified. Theterms conversion methacrolein and methacrylic acid is 79.3 percent. ofisobutylene, selectivity and single-pass yield EXAMPLE 3 which are usedherein are defined by the following A catalyst having a Composition f;\/;M equations- Te=l0:3:2:2 (atomic ratio) was obtained in a mannermoles of isobutylene converted moles of isobutylene fed carbon number ofeach product moles of each product X Conversion of isobutyleneSelectivity moles of isobutylene converted x 100% carbon number of eachproduct moles of each product X Single-pass yield )K 100% moles ofisobutylene fed The results of the experiments using the catalyst ofsimilar to that described in Example 1. The oxidative this invention areshown in the examples and a number conversion of isobutylene wasconducted under the of comparative examples, were conducted using theexsame reaction conditions described in Example 1. The perimentalprocedure described below. results obtained are shown in Table I,wherein the con- A 20 gram amount of a catalyst in tablet form withversion of isobutylene is 99.8 percent, the selectivities a diameter of3mm was placed in a fixed bed tubular of methacrolein and methacrylicacid are 67.2 and 10.2 reactor made of pyrex glass having an insidediameter percent respectively, and the composite single pass of 20mm.The reactor was immersed in a tubular elecyield of methacrolein andmethacrylic acid is 77.2 pertric furnace, and a gas mixture containingabout 5 mole cent.

EXAMPLES 4, 5, and 6 Te=10:2:3: l .6 (Example 6) were prepared in amanner similar to that described in Example 1. The oxidative conversionof isobutylene was conducted with the catalysts prepared in the mannerindicated. The results obtained are shown in Table 1, wherein theconversion of shown in Table I, wherein the conversion of isobutylene is89.7 percent, the selectivities of methacrolein and methacrylic acid are27.2 and 12.3 percent respectively and the composite single-pass yieldof methacrolein and methacrylic acid is 35.4 percent.

COMPARATIVE EXAMPLE 3 A catalyst having a composition of Sb:Te:Mo=l0:2:2 (atomic ratio) was obtained in a manner similar to thatisobutylene is 94.2 percent, the selectivities of methacdescrbed m 35 2iff that at; a l rolein and methacrylic acid are 72.6 and 6.21 percent i3 l e m g d e f f respectively and the composite single-pass yield of 3uty i i con i ti methacrolein and methacrylic acid is 74.2 percent for oi a 3 enpera ure 0 3 Example 4; the conversion of isobutylene is 92.3per- 5 0 H I h th cent, the selectities of methacrolein and methacrylicS 9 2 a e C i .9 m; acid are 74.8 and 5.2 percent respectively and thecomi 15(1) y 3 ls th F e g fg h f posite single-pass yield ofmethacrolein and methi sg gg i g i gz i; acrylic acid is 73.8 percentfor Example 5; and the conpield of metgacroleii and methacr 8 p 5version of isobutylene is 96.8 percent, the selectivities 2O g y ofmethacrolein and methacrylic acid are 70.8 and 6.7 percent respectively,and the composite single-pass COMPARATIVE EXAMPLE 4 yield ofmethacrolein and methacrylic acid is 75.0 per- A catalyst having acomposition of Mon-6:242 Cent for Example (atomic ratio) was obtained ina manner similar to that COMPARATIVE EXAMPLE 1 described in Example 1except that the antimony coml pound was not added in this case. Theoxidative con- A Q havmg CPmPQSmOn of y- 5 1 1 version of isobutylenewas conducted with the catalyst (atomic rat1o) was obtalned In a mannerSlml ar to t at obtained at a reaction temperature of 420C with 3described in Example 1 except that the molybdenum Contact time ofseconds compoufld not added thls Case and h oxldatwe The results areshown in Table I, wherein the converconversl?" oflsobutylelle wasconducted P sion of isobutylene is 93.7 percent, the selectivities oflyst 9 at a reacuon temperature of 435 C methacrolein and methacrylicacid are 62.0 and 4.6 a Contact of Secondspercent respectively, and thecomposite single-pass The results obtijlmed are shown m Table wheremyield of methacrolein and methacrylic acid is 62.4 perthe conversionofisobutylene 15 94.0 percent, the seleccent tivities of methacroleinand methacrylic acid are 57.6 and 6.3 percent respectively and thecomposite single- COMPARATIVE EXAMPLE 5 pass yield of methacrolein andmethacrylic acid is 60.0 A catalyst having a composition ofV:Mo:Te=6:8:1 percent. (atomic ratio) was obtained in a manner similarto that 40 described in Comparative Example 4, and the oxidativeCOMPARATIVE EXAMPLE 2 conversion of isobutylene was conducted over thecata- A catalyst having a composition of Sb:V:Mo=l0=2:2 lyst obtained ata reaction temperature of 400C with (atomic ratio) was prepared in amanner similar to that a contact time of 5.0 seconds. The resultsobtained are described in Example 1 except that the tellurium comshownin Table 1, wherein the conversion of isobutyl-- pound was not added inthis instance. The oxidative ene is 89.0 percent, the selectivities ofmethacrolein conversion of isobutylene was conducted with the cataandmethacrylic acid are 42.3 and 9.6 percent respeclyst obtained at areaction temperature of 440C with tively, and the composite single-passyield of methacroa contact time of 4.8 seconds. The results obtained arelein and methacrylic acid is 46.3 percent.

TABLE I Con- Catalyst Composition ver- Composite (in atomic ratio)Reaction Condition sion Selectivity 71 single-pass Sb V Mo Te W ReactionConc. Contact of MAL MAA Acetic CO; CO yield of MAL g pof iso- Ilme isoacid and MM A C butylcnc but- 7: ylenc 1 10 2 2 1 0 400 5.36 5.0 96.474.0 7.6 3.8 8.6 4.0 78.6 2 10 2 4 2 0 400 5.12 5.0 97.5 76.0 5.3 4.77.9 4.7 79.3 3 10 3 2 2 0 400 5.61 5.0 99.8 67.2 10.2 3.3 11.7 6.0 77.24 10 2 8 2 O 415 5.24 5.4 94.2 72.6 6.2 5.0 10.2 5.4 74.2 5 l0 2 3 6 0420 5.18 6.0 92.3 74.8 5.2 4.8 9.2 4.3 73.8 6 10 2 3 1.6 0 400 5.60 5.096.8 70.8 6.7 4.2 9.4 4.2 75.0 Com P rative Note:

MAL: Methacrolein MAA: Math-acrylic acid EXAMPLE 7 A 21.6 gram amount ofammonium paramolybdate (NH Mo O .4H O was dissolved in 400cc of waterand 11.6 grams of ammonium metavanadate NH VO were added to thesolution. The added material was dissolved by stirring over a hot waterbath. Then 4.8 grams of bismuth nitrate (Bi(NO .51-l O as a fine powder,and 16.0 grams of tellurium dioxide TeO were added to the solution withthorough stirring. Finally 73.2 grams of antimony trioxide Sb O wereadded and the solution was further stirred thoroughly.

The resulting solution was concentrated by evaporation and the residueobtained was dried. The dried residue was punched into tabloids with adiameter of 3mm, and was further dried and calcined at 500C for hours. Acatalyst having a composition of Sb V Mo ,Te Bi (atomic ratio) wasprepared in this manner.

The oxidative conversion of isobutylene was conducted with the catalystprepared at a reaction temperature of 400C with a contact time of 4.6seconds. The results obtained are shown in Table 11, wherein theconversion of isobutylene is 99.0 percent, the selectivities ofmethacrolein and methacrylic acid are 67.4 and 14.6 percentrespectively, and the selectivities of acetic acid, carbon dioxide andcarbon monoxide are 2.8, 8.6 and 5.0 percent respectively. As aconsequence, the single-pass yield of methacrolein and methacrylic acidwas 81.2 percent.

EXAMPLE 8 A catalyst having a composition of Sb V Mo Te Bi (atomicratio) was prepared in a manner similar to that described in Example 7.The oxidative conversion of isobutylene was conducted over the catalystprepared at a reaction temperature of 400C with a contact time of 4.6seconds. The results are shown in Table 11, wherein the conversion ofisobutylene is 99.5 percent, the selectivities of methacrolein andmethacrylic acid are 67.8 and 12.8 percent respectively and thecomposite single-pass yield of methacrolein and methacrylic acid is 80.2percent.

EXAMPLE 9 A catalyst having a composition of Sb V Mo Te W Bi (atomicratio) was prepared in a manner similar to that described in Example 7except that 100cc of an aqueous solution containing 3.9 grams ofammonium paratungstate was added to the solution prior to the additionof bismuth nitrate.

The oxidative conversion of isobutylene was conducted over the catalystobtained at a reaction temperature of 380C with a contact time of 4.6seconds. The results obtained are shown in Table 11, wherein theconversion of isobutylene is 99.2 percent, the selectivities ofmethacrolein and methacrylic acid are 63.4 and 15.8 percentrespectively, the single-pass yield of methacrylic acid is 15.7 percentand the composite singlepass yield of methacrolein and methacrylic acidis 78.6 percent.

EXAMPLE 10 A catalyst having a composition of Sb V Mo Te Tl (atomicratio) was prepared in a manner similar to that described in Example 7,except that an aqueous solution of thallium trichloride was used insteadof a solution of bismuth nitrate. The oxidative conversion ofisobutylene was conducted over the catalyst obtained at a reactiontemperature of 400C with a contact time of 5.0 seconds. The resultsobtained are shown in Table 11, wherein the conversion of isobutylene is96.8 percent, the selectivities of methacrolein and methacrylic acid are67.6 and 15.3 percent respectively, the single-pass yield of methacrylicacid is 14.7 percent, and the composite single-pass yield ofmethacrolein and methacrylic acid is 80.2 percent.

EXAMPLE 1 l A catalyst of a composition of Sb V Mo Te Tl (atomic ratio)was prepared in a manner similar to that described in Example 10. Theoxidative conversion of isobutylene was conducted at a reactiontemperature of 400C with a contact time of 5.0 seconds. The resultsobtained are shown in Table 11, wherein the conversion of isobutylene is94.9 percent, the selectivites of methacrolein and methacrylic acid are72.8 and 12.3 percent respectively, and the selectivities of aceticacid, carbon dioxide and carbon monoxide are 2.6, 6.3 and 2.8 percentrespectively. As a consequence, the singlepass yield of methacrylic acidwas 1 1.7 percent and the composite single-pass yield of methacroleinand methacrylic acid was 80.8 percent.

EXAMPLE 12 A 47.7 gram amount of ammonium paramolybdate (NH Mo O .,.41-1O was dissolved in 600cc of water and 31.6 grams of ammoniummethavanadate NHNO were added thereto. The vanadate material wasdissolved by stirring the mixture over a warm water bath. To thissolution was added cc of an aqueous solution containing 20.7 grams ofthallium trichloride TlCl .41l O and the solution was thoroughlystirred. Next, 28.7 grams of tellurium dioxide was added with stirringto the solution. Then, after 157.4 grams of antimony trioxide were addedand thoroughly mixed in the solution, 29.1 grams of diatomaceous earthwas added with continuous stirring. The resulting solution wasconcentrated by evaporation and the residue was dried. The dried residuewas punched into tabloids with a diameter of 3mm and was dried andcalcined at 500C for 5 hours. A catalyst of a composition of Sb, V Mo TeTl (atomic ratio) containing 10 percent by weight diatomaceous earthcarrier was prepared in this manner.

The oxidative conversion of isobutylene was conducted over the catalystobtained in this way at a reaction temperature of 400C with a contacttime of 4.2 seconds. The results showed a 99.1 percent conversion ofisobutylene, a 63.0 percent selectivity of methacrolein, and a 17.8percent selectivity of methacrylic acid. The selectivities of aceticacid, carbon dioxide and carbon monoxide were 3.9, 9.8 and 4.5 percentrespectively. As a consequence, the single-pass yield of methacrylicacid was, as shown in Table II 17.6 percent and the compositesingle-pass yield of methacrolein and methacrylic acid was 80.1 percent.

EXAMPLE 13 A catalyst having a composition of Sb, V Mo Te W Tl (atomicratio) was obtained in a manner similar to that described in Example 9except that thallium trichloride was used instead of bismuth nitrate.

When the oxidative conversion of isobutylene was conducted over thecatalyst obtained at a reaction temperature of 390C with a contact timeof 4.6 seconds, results were obtained which are shown in Table 11,wherein the conversion of isobutylene is 95.3 percent,

the selectivities of methacrolein and methacrylic acid are 64.8 and 16.0percent respectively, the single-pass yield of methacrylic acid is 15.2percent, and the composite single-pass yield of methacrolein andmethacrylic acid is 77.0 percent.

EXAMPLE 14 A catalyst of a composition of Sb V Mo Te w Bi Tl,, (atomicratio) was prepared in a manner similar to that described in Example 9except that thallium trichloride was added to the solution after theaddition of bismuth nitrate.

The oxidative conversion of isobutylene was conducted over the catalystprepared in this way at a reaction temperature of 386C with a contacttime of 4.6 seconds. The results obtained are shown in Table 11, whereinthe conversion of isobutylene is 98.3 percent, the selectivites ofmethacrolein and methacrylic acid are 61.7 and 16.5 percentrespectively, the single-pass yield of methacrylic acid is 16.2 percent,and the composite single-pass yield of methacrolein and methacrylic acidis 76.9 percent.

EXAMPLES 15, 16, 17

Catalysts of compositions (atomic ratios) of V2M03Te U (Example Sb 0V MoTe U0 4 (Example 16) and Sb, V Mo Te U (Example 17) were prepared in amanner similar to that described in Example 7 except that uranyl nitratewas added to the mixture instead of bismuth nitrate. The subsequentoxidative conversions of isobutylene with each catalyst prepared wereconducted at a reaction temperature of 380C with a contact time of 5.0seconds. As shown in Table II, the best catalytic performance wasobtained when the atomic ratio of uranium was about 0.2 in relation toSb=l0.

EXAMPLE 18 A catalyst of a composition of sb.,,v,Mo,Te U, Bi (atomicratio) was prepared in a manner similar to that described in Example 7,except that uranyl nitrate was added to the mixture after the additionof bismuth nitrate. The oxidative conversion of isobutylene wasconducted with the catalyst obtained at a reaction temperature of 380Cwith a contact time of 4.6 seconds. The results obtained are shown inTable 11, wherein the conversion of isobutylene is 98.0 percent, theselectivity of methacrolein is 64.2 percent, the single-pass yield ofmethacrylic acid is 17.0 percent, and the composite single-pass yield ofmethacrolein and methacrylic acid is 79.9 percent.

EXAMPLE 19 A catalyst having a composition of Sb V Mo Te W U Bi (atomicratio) was prepared in a manner similar to that described in Example 18with the addition of tungsten. The oxidative conversion of isobutylenewas conducted at a reaction temperature of 375C with a contact time of4.6 seconds. The results are shown in Table 11, wherein the conversionof isobutylene is 98.5 percent, the selectivities of methacrolein andmethacrylic acid are 61.3 and 15.1 percent respectively, the single-passyield of methacrylic acid is 14.9 percent, and the composite single-passyield of methacrolein and methacrylic acid is 75.3 percent.

EXAMPLE 20 The oxidative conversion of isobutylene was conducted in thepresence of 20 grams of the catalyst of Example 7. The composition ofthe gaseous mixture fed to the catalyst zone consisted of 5.6 molepercent isobutylene, 5.4 mole percent 1butene, 54 mole percent air and35 mole percent steam at an apparent contact time of 5.0 seconds at areaction temperature of 396C.

The results obtainedshowed a 94.8 percent conversion of isobutylene,selectivities for methacrolein and methacrylic acid of 70.5 and 14.5percent respectively and selectivities for carbon dioxide, carbonmonoxide and acetic acid of 7.5, 3.2 and 4.3 percent respectively. As aconsequence, the single-pass yield of methacrylic acid was 13.7 percentand the composite single-pass yield of methacrolein and methacrylic acidwas 80.6 percent. The results also showed that 27.8 percent of thel-butcne in the gaseous raw material had reacted, and that theselectivity for product butadiene was 69.2 percent and the selectivitiesfor trans-2 butene and cis- Z-butene were 1 1.4 and 15.6 percentrespectively.

EXAMPLE 21 The oxidative conversion of isobutylene was conducted with 20grams of the catalyst of Example 7 by feeding a gaseous raw material gashaving a composition of 10 mole percent of a C hydrocarbon fractioncomposed of 42 mole percent isobutylene,-27 mole percent l-butene, 10mole percent trans-2-butene, 7 mole percent cis-2-butene, 10 molepercent n-butane, 55 mole percent air and 35 mole percent steam with anapparent contact time of 5.0 seconds at a reaction temperature of 400C.

The results obtained showed a 95.7 percent conversion of isobutylene,selectivities for methacrolein and methacrylic acid of 69.0 and 14.2percent respectively, a single-pass yield of methacrylic acid of 13.6percent, and a composite single-pass yield of methacrolein andmethacrylic acid of 79.6 percent. The results also showed that 42.3percent of the n-butenes had reacted and the selectivity of butadienewas 67.6 percent.

COMPARATIVE EXAMPLE 6 An 11.6 gram amount of ammonium metavanadate NHqVOg was dissolved in 400cc of water and 200cc of an aqueous solutioncontaining 26.1 grams of uranyl nitrate UO (NO .6H O was added theretoand the combined solutions were thoroughly stirred. A 16.0 gram quantityof tellurium dioxide and 73.2 grams of antimony trioxide were added tothe solution while being thoroughly stirred. The resulting mixture wasconcentrated by evaporation and the residue dried. The dried residue waspunched into tabloids of 3mm diamter which were dried and calcined at520C for 5 hours. The catalyst obtained in this manner had a compositionof Sb V Te U (atomic ratio). The oxidative conversion of isobutylene wasconducted over the catalyst obtained at a reaction temperature of 420Cwith a contact time of 5.0 seconds. The results obtained are shown inTable 11, wherein the conversion of isobutylene is 87.7 percent, theselectivities of methacrolein and methacrylic acid are 53.5 and 6.1percent respectively, and the selectivities of acetic acid, carbondioxide and carbon monoxide are 3.0, 24.3 and 9.1 percent respectively.As a consequence, the single-pass yield of methacrylic acid was 5.3percent and the composite single-pass yield of methacrolein andmethacrylic acid was 52.3 percent.

COMPARATIVE EXAMPLE 7 A catalyst having a composition of Sb Mo Te U(atomic ratio) was prepared in a manner similar to that =10, and

12 Having now fully described this invention, it will be apparent to oneof ordinary skill in the art that many c=l-8, d=2-8, e=0.l-l, f=0.ll

What is claimed as new and intended to be covered by letters patent is:

I. A process for producing methacrolein and methacrylic acid whichcomprises reacting isobutylene with molecular oxygen in the vapor phasein the presence of a catalytic amount of a catalyst consistingessentially of a mixture of solid metal oxides represented by theempirical formula Sb V MO Te W M O wherein M represents at least oneelement selected from the group consisting of bismuth, thallium anduranium and 2. The process of claim 1, wherein the elemental tained at areaction temperature of 420C h a 20 atomic ratios of said empiricalformula are a contact time of 5.0 seconds. The results obtained are 1 4shown in Table ll, wherein the conversion of isobutylene is 94.3percent, the selectivities of methacrolein and methacrylic acid are 35.7and 7.2 percent respecchanges and modifications can be made theretowithout departing from the spirit or scope of the invention set forthherein.

wherein the elemental atomic ratios of said empirical formula havevalues of a=l0, b=0. l-lO, c=0.4-l5,

3. The process of claim 1, wherein the catalyst is supported by acarrier.

4. The process of claim 3, wherein said carrier is selected from thegroup consisting of diatomaceous earth, silica, alumina, titanium oxide,carborundum, and zirconium oxide.

5. The process of claim 1, wherein said oxidation of 30 isobutylene isconducted at a temperature in the range of 250 to 500C.

6. The process of claim 1, wherein said oxidation of isobutylene isconducted at a temperature in the range of 350 to 420C.

0.- lar to that described in Example 9 except that antimony trioxide wasnot added. The oxidative conversion of isobutylene was conducted overthe catalyst obtained described in Comparative Example 6 except that26.6 grams of ammonium molybdate were used instead of ammoniummetavanadate. The oxidative conversion of isobutylene was conducted overthe catalyst obtained at a reaction temperature of 425C with a contacttime as of 5.0 seconds. The results obtained are shown in Table II,wherein the conversion of isobutylene is 82.1 percent, the selectivitiesof methacrolein and methacrylic acid are 57.6 and 4.1 percentrespectively, the singlepass yield of methacrylic acid is 3.4 percent,and the composite single-pass yield of methacrolein and methacrylic acidis 50.7 percent.

COMPARATIVE EXAMPLE 8 A catalyst having a composition of Sb V Mo W Bi(atomic ratio) was prepared in a manner similar to that described inExample 9 except that tellurium dioxide was not added in this case. Theoxidative conversion of isobutylene was conducted over the catalystobtively, the single-pass yield of methacrylic acid is 6.8- percent, andthe composite single-pass yield of methacrolein and methacrylic acid is40.5 percent.

COMPARATIVE EXAMPLE 9 A catalyst having a composition of V Mo Te W gBiog(atomic ratio) was prepared in a manner simi at a reaction temperatureof 430C'with a contact time of 5.0 seconds. The results are shown inTable II,

7. The process of claim 1, wherein said oxidation of wherein theconversion of isobutylene is 87.2 percent, isobutylene is conducted at aContact time in the range the selectivities of methacrolein andmethacrylic acid of to 20 Secondsare 58.9 and 4.3 percent respectively,the single-pass The Process of Claim wherein the molecular oxyyield ofmethacrylic acid is 3.7 percent, and the comgen is Supplied in the formof air.

9. The process of claim 1, wherein said oxidation of isobutylene isconducted in the presence of an inert TABLE II Singlepass Yield MAL MAA

Reaction Condition Re- Cone.

action of isotemp. butylene time -pass yield of methacrolein andmethacrylic acid is 55.1 percent.

Ex. Catalyst Composition (in atomic ratio) Sb V Mo Te W posite singleIrllilllll- 28 2 063232462212 00.0 00000000000 0 B B W U B UUUBU U Note:MAL: Mclhacrulcin MAA: Mclhucrylic acid gaseous diluent.

10. The process of claim 9, wherein the inert gaseous diluent isselected from the group consisting of steam, nitrogen, and carbondioxide.

1 1. The process of claim 1, wherein isobutylene is admixed with anothersaturated or unsaturated hydrocarbon gas.

12. The process for producing methacrolein and methacrylic acid whichcomprises oxidizing isobutylene with a mixture of air and steam, in thevapor phase, at a temperature in the range of 250 to 500C in which theconcentration of isobutylene, air and steam are

1. A PROCESS FOR PRODUCING METHACROLEIN AND METHACRYLIC ACID WHICHCOMPRISES REACTING ISOBUTYLENE WITH MOLECULAR OXYGEN IN THE VAPOR PHASEIN THE PRESENCE OF A CATALYTIC AMOUNT OF A CATALYST CONSISTINGESSENTIALLY OF A MIXTURE OF SOLID METAL OXIDES REPRESENTED BY THEEMPIRICAL FORMULA SBAVBMOVTEDWEMFOY, WHEREIN M REPRESENTS AT LEAST ONEELEMENT SELECTED FROM THE GROUP CONSISTING OF BISMUTH, THALLIUM ANDURANIUM AND WHEREIN THE ELEMENTAL ATOMIC RATIOS OF SAID EMPIRICALFORMULA HAVE VALUES OF A=10, B=0.1-1-10, C=4-15, D=0.1-10, E=2, F=0-2AND G=16-127.
 1. A process for producing methacrolein and methacrylicacid which comprises reacting isobutylene with molecular oxygen in thevapor phase in the presence of a catalytic amount of a catalystconsisting essentially of a mixture of solid metal oxides represented bythe empirical formula SbaVbMocTedWeMfOg, wherein M represents at leastone element selected from the group consisting of bismuth, thallium anduranium and wherein the elemental atomic ratios of said empiricalformula have values of a 10, b 0.1-10, c 0.4-15, d 0.1-10, e 0-2, f 0-2and g 16-127.
 2. The process of claim 1, wherein the elemental atomicratios of said empirical formula are a 10, b 1-4, c 1-8, d 2-8, e 0.1-1,f 0.1-1 and g 16-127.
 3. The process of claim 1, wherein the catalyst issupported by a carrier.
 4. The process of claim 3, wherein said carrieris selected from the group consisting of diatomaceous earth, silica,alumina, titanium oxide, carborundum, and zirconium oxide.
 5. Theprocess of claim 1, wherein said oxidation of isobutylene is conductedat a temperature in the range of 250* to 500*C.
 6. The process of claim1, wherein said oxidation of isobutylene is conducted at a temperaturein the range of 350* to 420*C.
 7. The process of claim 1, wherein saidoxidation of isobutylene is conducted at a contact time in the range of0.5 to 20 seconds.
 8. The process of claim 1, wherein the molecularoxygen is supplied in the form of air.
 9. The process of claim 1,wherein said oxidation of isobutylene is conducted in the presence of aninert gaseous diluent.
 10. The procEss of claim 9, wherein the inertgaseous diluent is selected from the group consisting of steam,nitrogen, and carbon dioxide.
 11. The process of claim 1, whereinisobutylene is admixed with another saturated or unsaturated hydrocarbongas.